The flaw in Mozilla reported at the weekend turns out to have been a hoax. Mischa Spiegelmock, one of the researchers who found the alleged vulnerability has admitted that his presentation at the Toorcon conference was meant to have been a joke - but that was after Mozilla's researchers spent two days trying to find the problem.

Spiegelmock, who works for Six Apart, and Andrew Wbeelsoi had alleged that a vulnerability in the browser software could allow someone to execute malicious code through a memory corruption attack on Firefox.

But Window Snyder, who leads Mozilla's security team, said Spiegelmock had admitted to the company that the presentation was meant to be humorous, and he and Wbeelsoi had not actually achieved remote execution with the exploit code demonstrated at the show.

"At best, in some cases it will crash only the client," said Snyder. "That's all we've been able to verify at this point."

Spiegelmock put a statement on his LiveJournal blog, in which he includes a link to a statement he made that is posted on Snyder's Mozilla blog. (http://developer.mozilla.org/devnews/index.php/2006/10/02/update-possible-vulnerability-reported-at-toorcon/)

"The main purpose of our talk was to be humorous," according to the statement. "As part of our talk we mentioned that there was a previously known Firefox vulnerability that could result in a stack overflow ending up in remote code execution. However, the code we presented did not in fact do this, and I personally have not gotten it to result in code execution, nor do I know of anyone who has."

During the presentation, the hackers also said they knew of 30 other vulnerabilities in Firefox but Spiegelmock said that this was a claim from Wbeelsoi and that he knew nothing of further vulnerabilties.

ix Apart spokeswoman Jane Anderson said that the Toorcon presentation was a joke invented by two kids barely out of their teens who didn't understand the ramifications of their actions.

"It was all a parody," she said. Anderson added that Spiegelmock was not representing Six Apart at the show, and the company spent most of Sunday on the phone with Mozilla putting out fires and cooperating with the company to get to the bottom of the matter.

To make matters more embarrassing for Six Apart, the company's earliest investor, Joi Ito, is on Mozilla's board of directors.

Anderson added that Spiegelmock will not be terminated for his actions. "We all make mistakes," she said.

Snyder and the Mozilla team also are being good sports about the ordeal.

"Of course, we always prefer that security researchers report vulnerabilities to us so we can create a patch before customers are put at risk," she said. "But at this point he's been very cooperative and we're pleased he's chosen to work with us."

Still, Snyder said, "I know people who were working really hard here on Sunday probably have other things they'd rather be doing."

Additional reporting by Elizabeth Montalbano, IDG news service